To hopefully put a button on this Lithium topic for now: High capacity Marine Lithium Iron Oxide ("LiFePRo4") are engineered & designed for safety, but they are pretty new so some folks may want to wait it out a little longer. That said, LiFePro batteries are designed to be extremely safe for use on yachts, at the expense of efficiency and power density.
Lithium (LiOn) technology in 787 batteries, Tesla batteries, Dewalt batteries, scooter batteries, even handheld VHFs & iPhones are not the same thing at all--they are NOT LiFePro4 chemistry and those batteries are very dangerous if mishandled (i.e., punctured or shorted). They are designed for extremely high-power density (WHrs/pound) and we must be careful with them. A drawer full of loose Dewalt LiOn batteries with a bunch of sharp tools on a boat at sea is an accident/serious fire waiting to happen. A slightly damaged untended LiOn battery on a charger can overheat, swell, and explode. You can't put out the fire until all the Lithium is explosively consumed.
LiFePro battery house banks (what many folks have been installing on their sailboats and some powerboats for 8-10 years--because of their extremely high capacity, carefree usage, and long-lasting service life of 10-20 years) are proving to be extremely safe and frankly revolutionary. LiFePro batteries are safer because they were designed to be safe--due to the stable chemistry and the built-in battery management systems (BMSs). We all know that lead acid high-capacity batteries on a yacht must be installed and charged properly, or they will burn up wiring or explode battery acid all over the ER--or like mine once did, try to kill you in your sleep with Sulphur gas.
It's important to note LiFePro battery installations are not just "drop-in" solutions. They also require other (affordable) electrical upgrades to the yacht electrical system for safety due to the LiFePro characteristics. LiFePro banks can charge and discharge much faster than equivalent capacity AGMs so require smart chargers, alternators, monitors and fuses that can handle higher in-rush amperage. In my opinion, a modern well designed LiFePro system has now become affordable, efficient, safe and the way of the future.
The argument that it's inherently safer to sleep at anchor with a 20-40 year old GenSet running while AGMs are charging in the ER is likely to sound silly with time.